PHEV conversio using CAN-View and BMS+

Hello everyone, I decided to start a thread on my conversion using Norm's CAN-View and BMS+

I'm taking it slow so everyone be patient (don't you love that I already assume an audience waiting on my every post?)

Special thanks in advance to aminorjourney in the UK, of course to Norm in Canada, to "The Pilot" in Corvallis, Oregon.

Basic setup is this:
2008 Prius II Package 6 bought salvaged from minor front collision.
Two extra NiMH traction batteries both from 2008 Prius (I got lucky with that)
BMS+
Simple Voltage doubler charger (converts 170V AC Peak mains current to 340V) which under load drops to ~240V.
(Formula for calculating the 'sag' in voltage under load from wikipedia - drop in voltage is I/6fc*(4n^3+3n^2-n)where I is current, f is freq. c is capacitance, n is number of repeats in voltage doubler circuit)
Temperature and other protection in the charger

Experiments: Experiment 15
[ame="http://en.wikipedia.org/wiki/Voltage_doubler"]Voltage doubler - Wikipedia, the free encyclopedia[/ame]

 

How do I move a thread? I tried editing but didn't see anything.

The capacitor based doubler limits your current (in my limited understanding ) because the capacitors can only store up so much charge and then dump it in the little slice of time they have to work (1/60 second in US) The voltage is actually only doubled for open circuit, which makes sense - the caps are fully charged and are just sitting there getting warm waiting for you. Note that they didn't get to double in one period of the AC sine wave, maybe it took a couple cycles, I'll let you do the math. But as soon as you apply load such as prius battery, current races out of the capacitors and voltage drops. In the extreme, you could short circuit the doubler, in which case the capacitors would cease to contribute anything, being drained. In that case, the voltage is original mains, but rectified to I guess 120V. Or is it 170V? Damn. Anyway, it's a good way to look at it I think, your actual voltage is somewhere between full double and mains when under load. A little math and experimentation gives you a capacitance of 300-400 microFarads for up to 240V DC and ~4A. If you want your average current to go up, use bigger caps.

Now, the downside to this, which I think Vertex sees, is that although the average current is around 4 amps in my example, the pattern of current is giant spikes of current as the capacitors drain which quickly die off as voltage drops to current battery voltage.

I did a simulation in LT Spice and it showed spikes of current up to 45Amps in both positive and negative directions. These spikes last milliseconds, and I think they are what actually charges the battery, although I'm out on a dry, rotten limb at this point, having little theory to back me up. My thinking is this: The capacitors are what actually charges the battery. They are leapfrogging off mains in a sense.

Braking down hill of course pumps 100A at 300V into the battery, so no big deal I guess. I hope

 

Ha! It was lucky. I found them on ebay and the second one I got delivered for free since it was local! How lucky is that!!?? (Thanks to Alex for delivery)

We'll see how lucky I am after ramming home made electrons into them for a few months.

 

Not that lucky

Not that lucky!
Just free delivery

 

See reply in other thread. I'm still chugging along with 6 bats or 24AH of electricity. My power bill has gone up!